Impact tool



Aug 2, 1960 E. G/BOGGENBURK V2,947,283

IMPACT TooL Filed Feb. 4, 1955 2 Sheets5heet 1 EARL G. ROGGENBURK BYg//i 346e( AT ORNEY Aug. 2, 1960 I F..A G. ROGGENBURK 2,947,283 I IMPACTl TOOL Filed Feb. 4; 1955 2 sheets-sheet 2 1N V EN TOR.

EARL G. ROGGEN BURK F l 6.4

M@ ATTClEY@ ing the invention;

IMPACT TOOL Earl G. Roggenburk, 4120 Behrwald Ave., Cleveland, Ohio Filed Feb. 4, 1955, Ser. N0. 486,198

:4 Claims. (Cl. 121-33) This invention pertains to an impact tool and, more particularly, to a much lighter but equally effective impact tool compared to prior art tools and compared to the tool shown and described in my copending patent application Serial Number 404,747, tiled January 18, 19'54, now Paten-t Number 2,786,376.

In prior art impact tools a rotary fluid rotor.is driven at high rotary speed and by means of Various coupling devices is connected toa massive rotatable hammer which in turn, through various mechanisms, is intermittently caused to strike an anvil to deliver an impact blow. ln these prior art devices the rotary fluid rotor has been made as light as possible in order to obtain as rapid acceleration as possible ot the rotor and hammer, and various devices have been utilized to decouple the rotor from the hammer upon impact of the hammer with the anvil. the rotor is not of much assistance in delivering a blow, and represents to an appreciable degree a loss in the tool. The mass of the air rotor was kept at a minimum in order to reduce the forces involved when the hammer was suddenly stopped upon striking the anvil. lf the rotor were made heavy enough to appreciably contribute to the blow, the splines or other means for connecting the rotor to the hammer were usually eventually damaged in operation. v

An object of the present invention is to provide an impact tool such as a wrench, screwdriver or the like which is much smaller in size and light in weight, yet which is just as effective in impact action as any previous tool.

Another object of the present invention is to provide an impact tool wherein the mass of the rotary iluid rotor is effectively utilized to strike a blow. i

A further object of the present invention is to provide an impact tool wherein the uid rotor is the hammer.

iA fur-ther object of the present invention is to provide an impact tool having an absolute minimum of moving parts. l

It is a further object ot the invention to provide a unitary massive hammer and iluid rotor for an impact tool.

For a better understanding of the present invention, together with other and further objects thereof, reference yis had to the following description taken in connection i with the accompanying drawings, and its scope will be pointed out in the appended claims.

In the drawing, IFigure l is a sectional view of an impact tool embody- Figure 2 is a sectional view taken along line 2-2 Figure 1;

Figure 3 is a sectional view takenY alongline 3 3 of Figure 1; and

Figure 4 is a sectional View of the motor liner. In one aspect the invention lies in an impact tool comprising a housing Withinwhich thereis mounted for In many of these prior art devices the mass of i rotor which extends in a direction transverse to the axis rotation a massive fluid rotor. There is a bore in the of rotation of the rotor. A hammer pin is slidably mounted within' the bore and is eccentric with respect to the axis of rotation so that rotary motion of the fluid rotor tends to throw the hammer pin partially out of the bore. Output drive means are mounted for coaxial rotation with the fluid rotor and includes an anvil located in the circumferential path occupied by the portion of the hammer pin located outside of the bore when rotating to cause the hammer pin to strikethe anvil when centrifugal force causes the hammer pin to project out of the bore. Y

vIn the drawing there is shown an impact tool such as a wrench comprising a housing 1t)V within which there is mounted a hollow liner element 1'1, and Within the liner there is a massive rotorelement 12 having a plurality of radial slots 13 within each of which there is slidably positioned a vane 14. The massive rotor element 12 is eccentrically positioned with respect to the liner element 11. One end of the massive element 12 has a projection 15 which is internally threaded at 16. The inner race of a bearing 17 is mounted around the projection 15, and the outer race of the bearing is against an annular projection 18 carried by the end plate 20 which bears against the end of the liner 11 sealing shut one end ofthe hollow liner 111. A large bolt 21 screws into the projection on the massive element with a washer 22 therebetween in tight engagement with the inner race of the bearing, and .a threaded ring 24 is screwed onto the annular projection p l18 to rmly engage the outer race of the bearing thereby holding the bearing in place and gently holding the end plate 20 against thetliner ,1.1.

At the other end of the massive element 12 there is a flange 28 forming part of the massive element. -Flange 28 overlaps the liner 11 thereby sealing shut the other en d of the hollow liner. With end plate 20 closing one end and the ange 28 closing the other end all of the radial slots 13 are closed at both ends and each of the vanes 14 therein is free to move in a radial direction under iniluence of centrifugal forces until its end face 30 is in sealing engagement with theinner face of the liner 11. As is known in the art, expansion of compressed air or the like in the space between the massive element 12 and the liner 1-1 forces the massive member and its vanes to rotate very rapidly.

Forward of the ange 28 and preferably forming an integral part ofthe massive element 12 there projection formed of a large section 33 and a small section 34, each circular in cross-section transverse to the axis of the tool. The smaller section 34 is mounted in .a bore 35 in a driven member 36, and can rotate with respect thereto.

Tlhe driven member 36 is mounted inside aV sleeve bearing 38 for relative rotation with respect thereto, and an O ring 39 is located between the two members to prevent escape of lubricant and compressed air. rIg'he bearing 38 is held by a reduced portion 10 of the housing 10, and -a threaded plug 40 is located through the housing adjacent the end of the bearing 38 for providing access to the interior for lubrication purposes. Y

The end 41 of the driven member 36 is square in crosssection and is located outside of the housing 10 for engagement with various types of tools to `be driven. The output drive means 36, 41 includes an anvilportion 43 located in the circumferential path outside of the large section 33 of the massive' element 12, and within this large section 33 of the massive element there is a bore 50 extending perpendicular to the axis of rotation of the massive element 12. A pin 51 is connected across this bore and is held in there by the outwardly-turned ilange 36 of the driven Amember 36.. Oneend of a springYS-vz kPatented Aug. 2, 14960l is hooked over the pin 51 and the other end of the spring is hooked over a pin 55 mounted across the bore 56 in the hammer pin 57. A cushioning spring 8 is positioned between the' pin'51 andthe end of the'hammer pin' 57.`

The hammer pin 57 is slotted' at 60 and a stop pin 59 is secured in the wall of the larger section 33 to limit the extent of motion of the hammer pin 57 out of the bore 50 under centrifugal force asV the massive means 12 rotates. Further details of this construction and its operation wil-l be found in my aforesaid copending application Serial Number 404,747, now Patent Number 2,786,376. Briefly, as the massive means reaches the proper rotary speed under driving forces of compressed air the hammer pin 57 liies out against the bias of spring 52 and it hits the anvil 43 a sharp blow. All of the momentum of the massive rotor goes into the blow which is turned into a rotary motion bythe output drive means 36 and applied to an external tool such as to a socket for turning 'a nut or to a screw driver. When the rotating massive means 12 stops and rebounds by the work being done spring 52 pulls the hammer pin 57 back into the bore 50 so that it clears the anvil, permitting rapid acceleration of the massive means and another blow. The spring 58 cushions the return of the hammer pin.

A unique feature of the hammer of this invention lies in the solid, massive, integral rotor and hammer mechanism. Prior to this invention the art has tried to make the air rotor and vane structure as light as possible, and often the rotor was not tightly coupled to the hammer. When the hammer reached proper speed it would deliver a blow to the anvil, and during this sharp blow the rotor was permitted to slip with respect to the hammer.

`In the present construction the rotor of the moto-r and the hammer are the same, resulting in an impact tool which is much shorter and lighter 'than prior art tools, yet the mass of the rotor (hammer) system is high and 'the tool exerts a forceful blow.

By combining the functions of the light weight air driven rotor and the massive hammer into one integral massive element which serves both purposes a much better tool is provided since it is smaller in overall size and weight, has fewer parts and the remaining pants are less expensive. Prior to this invention there was usually a splined shaft coupling the rotor to the hammer necessitating expensive machinery operations on both the male and female splined portions. Also, in prior devices the air rotor itself was extensively machined to make it hollow to reduce its weight. Accordingly, it will be seen that the present tool not only has fewer parts but the parts which are in the tool require less machin-ing and accordingly are less expensive. The result of the invention is a smaller, lighter, less expensive tool which is just as good as the best prior art tools in impact action and air consumption.

In the operation of the impact tool compressed fiuid, such as compressed air or the like, is admitted through the end connection 70, through the trigger 7.1 actuated valve 72, through the opening 73, through passage 74 to opening 75. With the Forward-Reverse valve lever 76 in the forward direction (to right-hand side of the drawing) the port 77 is connected to the port 78 by means of the groove 79 around the valve body 80. Port 78 communicates with the groove 81, Fig. 2, causing air under pressure to be admitted to the bore of the motor to drive it in a forward direction. The enlarged left-hand end of the valve body 80 prevents air from being admitted through port 84.

The air admitted into the bore of the motor drives the massive motor element 12 and is exhausted to atmosphere out of the primary exhaust port 90 in the housing liner 1v1 and in the housing of the tool. The exhaust port 90 is 180 degrees around the rotor from the input port 78, and as the v-anes 14 move from the locationhadjacent the primary exhaust port 90 toward the inlet port 78 they recede into the massive body 12 due to the eccentricity of the liner 11. Thus there is a space between the rotor, its receding vanes 14 and the liner 1v1 which is being reduced in size and which must be exhausted of its air. Failure to exhaust this air would result in compression of the air therein with consequent reduction in the power of the tool.

When the tool is rotating in the forward direction air is being admitted through port 7 S into the groove 85 in the inner surface of the liner 111', and the other groove 8.1 acts as a secondary exhaust port, the exhaust air passing out through the open port 84 into the space 91 in the housing 92 around the forward-reverse valve 80 and then to the exhaust groove 93 extending around the outside surface of the liner to the port 94 in the tool housing to atmosphere.

When the tool is running in the reverse direction the lever 76 is pushed inwardiy to' connect'port `84 and groove 81 to the air supply in the groove 79 thereby admitting air into the rotary motor at a location on the other side of the line where the rotor body is in contact with the inner surface of the liner. As shown in Figure 2 this contact line is immediately above the valve 80 and extends back into the paper. This drives the rotor 12 in the opposite direction and groove 85 serves as the secondary exhaust, communicating with port 78 which opens into the space 95 within the valve housing 92, which in turn exhausts out through groove 96 to the opening 97 in the housing for the tool,

With the reversing lever 76 pushed to the left, as seen in Fig. l, the enlarged left-hand endy of the valve body clears port 84, allowing compressed air in the groove 79 to be admitted to the bore of the motor through groove (Fig` 3) to drive the motor in the reverse direction. The enlarged right-hand end of the valve body 80 seals port 78 during reverse driving of the motor.

The Forward-Reverse lever 76 is shown in its intermediate position wherein the two enlarged ends of the valve body 8'0 each seal off one of the .ports 7-8, `84 into the bore of the motor. In this position the tool is shut off from its air supply and is not operating.

By positioning the lever 76 between the shut-off position and the full-forward position or the full-reverse position, the lever 76 becomes a throttle valve for both directions of operation. t

While there have been described what are at present considered to be the preferred embodiments of this invention, it will be obvious to those skilled in `the art thatl various changes and modifications may be made therein without departing from the invention, and it is, therefore, aimed in the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.

What is claimed is:

'1. An impact tool comprising a housing, a stationary liner within said housing, a rotor eccentrically mounted within said stationary liner, said liner comprising a cylinder having in its wall a bore'extending in a direction parallel to the axis of said cylinder and having a rst port extending from said bore to the inside of said liner and having an air inlet port, a non-rotatable reversing valve slidably mounted within said bore, and manually operable means connected to said valve and extending outside of said bore for moving the valve axially within said bore to cover and uncover said first port.

2. An impact tool as set forth in claim l, further characterized by a first groove in the inner wall of said liner one end of which communicates with said first port and which extends circumferentially part way around the said inner wall in the direction of rotation of said .rotor when said rotor is rotating in the forward direction.

3. An impact tool as set forth in claim l, further characterized by a second port extending from said bore to lthe inside of said liner and by a second groove in the inner 5 wail of said liner one end of which communicates with said second port and which extends oircumferentially part way around the said inner wall in direction of rot-ation of said rotor when said rotor is rotating in the reverse direction, sa-id reversing valve opening one of sa-id valves and closing the other upon being moved.

4. An impact tool as set forth in claim 3, funther characterizedby said bore being round in cross-section and by. said reversing valve comprising a cylindrical piston having a circumferential groove always in communication with said air inlet port, said reversing valve sealing one of said .ports as said circumferential groove communicates with the other port.

References Cited in the le of this patent UNITED STATES PATENTS Taylor May 1, 1906 Duntley Sept. 24, 1907 Aintsberg Apr. 20, 1937 Fosnot Feb. 25, 19411 Warren Aug. 14, 1945 Dobie Jian. 21, 1947 Sturrock Oct. 7, 1947 Webb Apr. 1, 1952 Disser Aug. 26, 1952 

